The field of the present invention is automatic fueling systems for vehicles.
The fueling of vehicles without manual intervention is currently being explored using a variety of approaches. A number of barriers exist to the successful implementation of automatic fueling systems; and yet substantial advantage is anticipated by the implementation of a successful system.
The lack of uniformity among vehicles poses a first and very substantial barrier to automatic fueling. It is anticipated that fueling stations must accommodate conventional vehicles with fuel ports located on either side of the vehicle, at varying heights and at varying distances from other features of the vehicle. They also must anticipate light duty trucks, vans and the like with even more widely divergent fuel port locations as well as cap mechanisms. Truck service stations servicing tractor-trailer rigs and other large trucks offer even greater challenges in the diversity of fuel ports. The cap and entry also provide great variety among vehicles.
In addition to the mechanical variety of equipment served, other requirements are of concern. Possible marring of the vehicle or spillage of fuel are highly objectionable. Communication regarding the product desired, the financial transaction and the like must be handled accurately and privately at the point of sale. Avoiding any consequences from mistakes by vehicle operators forms an even greater challenge to the concept of automatic fueling.
In addressing the foregoing problems, a variety of approaches have been developed for the fueling system. A first approach has been to completely change the vehicle fuel tank so as to accommodate specific filling techniques. One such device is illustrated in U.S. Pat. No. 4,681,144 which requires a fuel entry port below the vehicle tank with a pump and delivery mechanism located beneath the driveway. Another approach has been to use an overhead mechanism and sophisticated locating system in an effort to accommodate the very wide variety of fuel port placements. The overhead system attempts to be universally flexible in terms of locating and engaging the vehicle fuel port somewhat regardless of its location on the vehicle. Thus, systems have been contemplated which have such varying approaches as to require an all new fuel system on the vehicle to very rigorous internal flexibility to accommodate wide variety in fuel port locations.
Certain of the proposed systems require changes to the vehicle fuel port as noted above. Traditionally, the fuel port includes an entry port with a threaded cap or bayonet coupling. A cover coplanar with the body is typically pivotally mounted over the fuel cap with most modern automobiles. Practical automatic systems have not been developed which can accommodate the wide variety of such devices inhibiting access to the entry port of the fuel tank. One device which accommodates an automatic system without substantial change to the fueling equipment on the vehicle is illustrated in U.S. Pat. No. 5,163,473, the disclosure of which is incorporated herein by reference.
The advantages of automatic fueling are substantial. A large amount of fueling is performed by the vehicle operator today rather than by service station attendants. Albeit the choice is often made by the operator to fuel their own vehicle based on a marginal advantage in price, concerns regarding personal safety, cleanliness and mere inconvenience exist. Untrained and inattentive people operating the refueling systems also can result in excessive discharge of fuel vapors into the atmosphere, spillage on the ground and on the vehicle and overfill. Vehicle operators doing the fueling also can impede sales at busy stations. Constraints based on safety such as fuel flow rate have also been imposed based on the perceived competence of the untrained person acting to fill the vehicle. All of these circumstances and concerns can be eliminated through the employment of an automatic fueling system.
Fueling systems and fuel tank systems have been developed and improved in a step-by-step process which has resulted in complication and compromise. Two principal areas of concern are pollution controls and crash safety. Among current systems for delivering fuel, vapor recovery through the fuel nozzle provides a marginally effective mechanism for reducing pollution. Upon the filling of a tank, the gaseous mixture including polluting vapor is displaced. Such current systems include counterflow of vapor within the inlet pipe and through an annular passage in the nozzle to the station tank. Such flow can create problems, premature shutoff and burping. Further, a relatively efficient seal at the nozzle is necessary. As flow resistance of vapor back into the station tank is substantially greater than simple release into the atmosphere, leakage is almost-a constant problem. Techniques have been contemplated for passing the vapor through a recovery system with the entrained air released to atmosphere. Such a system contemplates a vent on the vehicle itself. However, pressure is required to pass the vapor through the collecting system. This again requires a substantial seal at the pump nozzle. The ability to clear the collection system is also a problem.
Another area of concern affecting vehicle fuel tanks is the lack of crash worthiness. Today tanks can be made relatively strong and burst resistant. However, the fuel filler pipe remains vulnerable and relatively exposed beneath sheet metal. Side impact, shearing impact and rollover have the possibility of damaging or detaching the filler pipe with potentially disastrous consequences.